(1) Field of the Invention
The present invention relates to image display devices such as an ultrasonic diagnostic device and a CT (Computerized Tomography) device, and particularly to an image processing technology for a tomographic image obtained by irradiating an examined object with ultrasound, X rays and the like.
(2) Description of the Prior Art
An image display device irradiates an anatomy (a test subject) with a diagnostic signal. (hereafter called “signal”) such as ultrasound and X rays, receives a signal reflected from the anatomy or a signal passing through the anatomy and executes imaging of the inside of the anatomy based on the received signal. In recent years, such an image display device has been widely used in industry and clinical medicine fields. Representative examples of such devices are an ultrasonic diagnostic device using a reflected signal and a CT device using a signal that passes through.
These image display devices can measure the anatomy and execute imaging in real time with the performance of a calculating machine, especially the processing speed, improving. In particular, in the clinical medicine field that needs high time resolution starting from circulatory organs, since a tomographic image of the anatomy is provided in real time, it is possible to quickly diagnose an affected part and the like.
By the way, in a real-time diagnosis, when an operator wants to measure a function, volume and the like of an examined object that operates cyclically, it is necessary to acquire a synchronization signal by some kind of method.
FIG. 1 is an outside view of a conventional ultrasonic diagnostic device 50. As shown in FIG. 1, the ultrasonic diagnostic device 50 is made up of a display device 51, a main unit 52, a probe 53 and an electrode for electrocardiogram (ECG) 54.
The display device 51 is a display device with a liquid crystal, CRT (cathode-ray tube) or the like to display a tomographic image obtained by echography or the like and necessary information. It has a touch panel and the like to accept an input from an operator.
The main unit 52 includes a send/receive circuit that controls transmission/reception of the ultrasound through the probe 53, a signal/image processing circuit made up of a DSP (Digital Signal Processor), RAM (Random Access Memory) and the like and a liquid crystal display that has a group of switches, a mouse and a touch panel to accept the input from the operator. Additionally, the main unit 52 receives an ECG signal through the electrode for ECG 54.
The probe 53 is a search unit made up of an ultrasound vibrator, and an acoustic lens and the like to send/receive the ultrasound.
As just described, the conventional ultrasonic diagnostic device 50 acquires the ECG signal as a synchronization signal from the test object through the electrode for ECG 54.
However, in the case of the conventional ultrasonic diagnostic device, since the above-mentioned synchronization signal is inputted into the ultrasonic diagnostic device through the special-purpose electrode for ECG 54, the ultrasonic diagnostic device needs a special-purpose circuit and a special-purpose cable, and therefore the cost for diagnosis becomes high, and at the same time space to set up an external device is necessary.
In addition, for use in the clinical medicine field, since it is necessary for a patient who is a subject for measurement to wear a measuring instrument to measure or extract the synchronization signal, there is a burden for the patient in both mind and body.
As just described, when making a diagnosis using the synchronization signal, generally the external device is necessary and the subject for measurement also needs to wear the measuring instrument, and therefore, there is a drawback that it is complicated and the measurement cost is high.